Technical Field
The present invention relates to a sensor output determination apparatus which determines whether or not outputs of a plurality of sensors are normal.
Related Art
An inverter is known which controls currents flowing through phases of a three-phase motor and detects the currents by current sensors (JP-A-2013-118746).
In many cases, a controller controlling a switching circuit of an inverter is housed in a housing of the inverter. In this case, output voltage of a current sensor is inputted to the controller. The controller determines whether or not the output voltage of the current sensor, that is, a current value, is normal. If the current value of each phase is not abnormal, the controller controls the switching circuit based on the current value of each phase.
A controller provided outside the housing of the inverter may control the switching circuit of the inverter. In this case, the distance between the current sensor and the controller is longer compared with a configuration in which the controller is housed in the housing of the inverter. Thus, considering noise easily superimposed on the output voltage of the current sensor, output voltage of the current sensor (analog signal) is required to be converted into a digital signal so as to be transmitted to the controller. However, since the digital signal representing a current of each phase (output voltage of the current sensor) has many bits, the amount of data to be transmitted cannot be prevented from increasing.
Note that, the above condition is mostly common not only in the configuration in which whether or not the current of each phase of the three-phase motor is normal is determined, but also to the configuration in which whether or not outputs of a plurality of sensors are normal is determined.